Command blocks's @s breaks on Bukkit. This fixes it for close interactions.

CommandBlockEvents.java

package cl.bgmp.lobbyx.listeners;

import cl.bgmp.lobbyx.events.PreciseCommandBlockEvent;
import org.bukkit.Bukkit;
import org.bukkit.block.Block;
import org.bukkit.block.BlockFace;
import org.bukkit.block.BlockState;
import org.bukkit.block.CommandBlock;
import org.bukkit.command.BlockCommandSender;
import org.bukkit.event.EventHandler;
import org.bukkit.event.EventPriority;
import org.bukkit.event.Listener;
import org.bukkit.event.block.Action;
import org.bukkit.event.player.PlayerInteractEvent;
import org.bukkit.event.server.ServerCommandEvent;

/**
 * Handles commands sent via @{@link BlockCommandSender} and replaces the broken variables in
 * Bukkit, to then dispatch the involved command via @{@link
 * org.bukkit.command.ConsoleCommandSender}
 */
public class CommandBlockEvents implements Listener {
  private static final BlockFace[] faces = {
    BlockFace.DOWN, BlockFace.UP, BlockFace.NORTH, BlockFace.EAST, BlockFace.WEST
  };

  @EventHandler(priority = EventPriority.MONITOR)
  public void onPlayerInteract(PlayerInteractEvent event) {
    final Action action = event.getAction();
    if (action != Action.PHYSICAL) return;

    final Block block = event.getClickedBlock();
    if (block == null) return;

    CommandBlock commandBlock = null;
    for (int i = 0; i < 6; i++) {
      BlockState nearby = block.getRelative(faces[i]).getState();

      if (nearby instanceof CommandBlock) {
        commandBlock = (CommandBlock) nearby;
        break;
      }
    }

    if (commandBlock == null) return;

    final PreciseCommandBlockEvent preciseCommandBlockEvent =
        new PreciseCommandBlockEvent(event.getPlayer(), commandBlock);
    Bukkit.getServer().getPluginManager().callEvent(preciseCommandBlockEvent);
  }

  @EventHandler(priority = EventPriority.HIGH)
  public void onCommandBlockEvent(ServerCommandEvent event) {}

  @EventHandler(priority = EventPriority.MONITOR, ignoreCancelled = true)
  public void onPreciseCommandBlockEvent(PreciseCommandBlockEvent event) {
    String command = event.getCommand().replaceAll("@s", event.getPlayer().getName());
    Bukkit.getServer().dispatchCommand(Bukkit.getConsoleSender(), command);
  }
}

PreciseCommandBlockEvent.java

package cl.bgmp.lobbyx.events;

import org.bukkit.block.CommandBlock;
import org.bukkit.entity.Player;
import org.bukkit.event.Event;
import org.bukkit.event.HandlerList;
import org.jetbrains.annotations.NotNull;

public class PreciseCommandBlockEvent extends Event {
  private static final HandlerList handlerList = new HandlerList();

  private final Player player;
  private final CommandBlock commandBlock;
  private final String command;

  public PreciseCommandBlockEvent(Player player, CommandBlock commandBlock) {
    this.player = player;
    this.commandBlock = commandBlock;
    this.command = commandBlock.getCommand();
  }

  public Player getPlayer() {
    return player;
  }

  public CommandBlock getCommandBlock() {
    return commandBlock;
  }

  public String getCommand() {
    return command;
  }

  public static HandlerList getHandlerList() {
    return handlerList;
  }

  @Override
  public @NotNull HandlerList getHandlers() {
    return handlerList;
  }
}